Valve repsonsive to temperature changes over a limited range

ABSTRACT

A fluid flow metering valve which varies effective flow area in response to temperature changes over a limited temperature range. The valve core, having a conically shaped end positioned in the fluid flow port, expands freely as temperature increases to a predetermined value from a temperature below that value. Thereafter, an abutment in the valve casing is engaged by a shoulder on the valve core to prevent the conically shaped end of the core from advancing further into the port, with additional expansion of the core being accommodated at the opposite end of the casing. A spring retains the core in the casing and returns it to its original position upon a decrease in temperature to and below the predetermined value.

United States Patent Gifford [54] VALVE REPSONSIVE TO TEMPERATURECHANGES OVER A LIMITED RANGE [72] Inventor: Robert T. Gifford, YellowSprings,

Ohio

[73] Assignee: Vernay Laboratories, Inc., Yellow Springs, Ohio [22]Filed: April 9, 1971 [21] Appl. No.: 132,666

[52] US. Cl ..236/102 [51] Int. Cl. ..G05d 23/275 [58] Field of Search..236/102, 101, 93, 87

[56] References Cited UNITED STATES PATENTS 1 Oct. 10, 1972 3,322,3455/1967 Getz ..236/93 Primary Examiner-Edward J. MichaelAttorney-Marechal, Biebel, French & Bugg [57] ABSTRACT A fluid flowmetering valve which varies effective flow area in response totemperature changes over a limited temperature range. The valve core,having a conically shaped end positioned in the fluid flow port, expandsfreely as temperature increases to a predetermined value from atemperature below that value. Thereafter, an abutment in the valvecasing is engaged by a shoulder on the valve core to prevent theconically shaped end of the core from advancing further into the port,with additional expansion of the core being accommodated at the oppositeend of the casing. A spring retains the core in the casing and returnsit to its original position upon a decrease in temperature to and belowthe predetermined value. 2,966,170, 12/1960 Raulms ..236/93 X 3,014,66412/1961 Meyer et al ..236/81 14 Claims, 3 Drawing Figures 4 l8 4 44 36 ZJ a 2 6 34 k f 42 [2 38 32 l6 PATENIEDncI I972 3.696.997

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0 2o so 80 I00 I20 I40 I I 200 220 DEGREES FAHRENHEIT INVE/VT'OR ROBERTT. GIFFORD A TTOR/VE Y8 VALVE REPSONSIVE TO TEMPERATURE CHANGES OVER ALIMITED RANGE CROSS REFERENCE TO RELATED APPLICATION THERMALLYRESPONSIVE VALVE AS- SEMBLY, by Robert T. Gifford, Ser. No. 132,494,filed Apr. 8, 1971.

BACKGROUND OF THE INVENTION In the above noted, related application avalve assembly is disclosed in which a unitary, rod-like valve member isreceived ina valve casing with one end of the valve member attached tothe casing and the opposite end projecting outwardly thereof into afluid flow port. The diameter of the valve member is sufficientlysmaller than the internal bore of the valve casing to permit the mainbody of the valve member to move within the casing and the materials ofwhich the casing and valve member are constructed are selected such thatthe coefficient of linear thermal expansion of the valve member isappreciably greater than that of the casing.

The free end of the valve member projects outwardly of the casing sothat when the casing is attached to the wall of a member having a flowport therein through which the fluid flow is to be regulated, theoutwardly projecting end of the valve member is positioned in the fluidflow port. With.this construction an increase in temperature will causethe valve member to expand and advance its outwardly projecting endfarther into the fluid flow port. This results in a decrease in theeffective flow area through the port. A decrease in temperature ofcourse, will result in an increase in effective flow area as the valvemember contracts and in this way the flow of fluid through the port isregulated in response to temperature changes.

While the above described construction functions effectively in itsintended environment, it will be seen that the effective flow areathrough the flow port will be continuously decreased in response toincreases in temperature. In certain installations, however, it isdesirable to set a lower limit for effective flow area regardless offurther temperature increases. In the idling inlet port of a carburetor,for example, while it is desirable to decrease the effective flow areaof the port in response to increases in temperature, there is a certainminimum effective open area which must be maintained regardless ofcontinued temperature increases. Obviously, in a valve construction inwhich movement of the valve member is unrestrained temperatures may beencountered which are high enough to close the effective flow area belowthe minimum desired or even close it completely.

SUMMARY OF THE INVENTION The present invention provides a valve assemblywhich is responsive to temperature changes over a limited range ofvalues. Thus, as the temperature rises above a first value, which isbelow some preselected temperature, the valve member will expand,advancing its flow regulating end farther into the flow port with whichit is associated, thereby reducing the effective area of the flow port.However, after the valve member has expanded a certain predeterminedamount, at which point the valve member will be at the preselectedtemperature, an outwardly projecting shoulder on the valve memberengages an inwardly projecting shoulder on the casing within which it ismounted to prevent further advance of the conically shaped end of thevalve member in any appreciable amount.

A further increase in temperature above the preselected temperature, andthus, further expansion of the valve member, is accommodated at theopposite end of the casing, where the opposite end of the valve memberadvances in opposition to the pressure of a spring mounted in the casingat that point. As a result, after the temperature has reached somepredetermined value and the effective open area of the flow port hasbeen reduced to a predetermined amount, the effective area of the flowport remains relatively constant regardless of continued temperatureincreases.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view, partly in section,showing the valve assembly with the valve core thereof in a firstposition;

FIG. 2 is a view similar to FIG. 1, but showing the valve core in asecond position thereof; and

FIG. 3 is a graph comparing the travel of the valve member of thepresent invention in response to temperature change to the travel of avalve member in which movement thereof is unrestrained.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference initially toFIG. 1 of the drawings, it will be seen that a valve assembly inaccordance with the present invention includes a valve casing 10 havingan internal bore 11 and an externally threaded portion 12 extending fromadjacent one end 14 thereof to an enlarged opposite end 16. At the end14 of the casing a shoulder projects radially inwardly into the bore 11to define an abutment 18 at that point. At its enlarged end 16 ashoulder or stop member 22 is defined by a portion projecting outwardlyof the bore 1 1.

Received within the casing 10 is an elongated, unitary, rod-like valvemember or core 24 having a conically shaped, fluid flow regulating end26. The valve core 24 is also provided with an outwardly projectingshoulder 28 positioned in opposition to the inwardly projecting abutment18 of the valve casing. The opposite end of the valve core 24 isprovided with an enlarged head portion 30 to provide an outwardlyprojecting shoulder 32 positioned in opposition to the shoulder 22 ofthe casing 16.

A retainer 34 is force fitted into the enlarged open end of the casing16 and serves to retain a spring member 36 mounted in a pocket 38 in theend of the valve member or core 24. The valve assembly thus describedmay be readily fixed within a threaded opening of a member 40 with whichit is associated by means of the external threads 12 thereof engagingcomplementary threads 42 formed in the wall of the member 40.

Thus, the casing 10 is threaded into the portion 42 of the member 40 toobtain the desired clearance between the conically shaped end 26 of thevalve core 24 and the flow port 44 at a preselected temperature. A coilspring 46 encircles the outwardly projecting portion of the casing 10and bears against the member 40 at one end and the enlarged head-16 ofthe casing at its opthe casing within the threaded portion of the member40.

In operation, assume that the temperature is below the preselectedtemperature such that the position of the core 24 within the casing isas shown in FIG. 1 of the drawings. Fluid flow may be in the directionindicated by the arrows in FIGS. 1 and 2 although it will be apparentthat the flow direction could be reversed. In this position it will benoted that the outwardly projecting shoulder 28 is spaced from theabutment 18 formed by the inwardly projecting portion of the casing 10and that the under surface of the enlarged head 30 of the core 24 isseated against the outwardly projecting shoulder 22 of the casing 10 andheld in this position by means of the spring 36.

If the temperature thereafter increases, the core 24 will expand,causing its conically shaped end 26 to advance farther into the flowport 44. This advance will continue as the temperature increases furtheruntil the shoulder 28 engages the abutment 18 at the preselectedtemperature, with additional advancement being negligible since it iscaused only by the expansion of the relatively short section of the coreextending from adjacent the outwardly projecting shoulder 28. Continuedincrease in temperature and commensurate expansion of the core 24 willbe accommodated in the enlarged end 16 of the casing by movement of thehead 30 in opposition to the spring member 36.

This, as seen in FIG. 2, will cause the under surface 32 of the head 30to move from engagement with the outwardly projecting shoulder 22,compressing the spring 36. Of course, as the temperature thereafterdecreases, the spring 36 will first urge the shoulder 32 into engagementwith the stop 22 and further contraction of the core 24 will cause theshoulder 28 to become disengaged from the abutment l8, retracting theconically shaped end 26 of the core 24 from the flow port 44 and therebyincreasing the effective flow area therethrough.

With reference to FIG. 3 of the drawings it will be noted that thetravel of the conically shaped end of the core 24 in response to changesin temperature is essentially the same as that of a valve assembly ofthe type described in the above noted related application until somepredetermined advancement of the core 26, as indicated by the letter Aon the curve, is reached. Thereafter, continued increase in temperaturewill result in only negligible travel of the end 26 of the core, asindicated by that portion of the curve labelled B, as contrasted to thecontinued travel of a corresponding portion of a core in which movementthereof is unrestrained, as indicated by the portion of the curvelabelled C in FIG. 3 of the drawings.

Of course, it is necessary to dimension the length of the core 24 withrespect to the length of the bore of the casing 10 as well as properlyselect materials for the core and the casing having coefficients oflinear thermal expansion to give the desired results. In this regard ithas been found that the valve casing may be formed of a material such assteel having a coefficient of linear thermal expansion of approximately6 X l0 I!l! .iBl![F.-L?l b9ll8h a 049, W 9"! glass filled, relativelyrigid, organic polymer, such as nylon, will also functionsatisfactorily.

The material of which the core is formed must have an appreciably highercoefficient of linear thermal expansion and desirably is at least threetimes greater than the thermal coefficient of expansion of the valvecasing. In constructing the valve core various relatively rigid, organicpolymers, such as nylon, polyethylene, acetal resins, acrylics andpolyvinylidene fluoride, have been found satisfactory. Thus, using steelas the casing material and forming the core of polyvinylidene fluoride,the coefficient of linear thermal expansion of the core will beapproximately thirteen times greater that that of the casing or shell.

Obviously, however, a wide variety of materials may be utilized inpracticing the present invention and with various combinations ofreadily available materials the range of differences in coefficients oflinear thermal expansion will range from about 3 to 25. The onlyrequirements are that the coefficients of linear thermal expansion ofthe core and the casing are sufficiently different to give appreciablecore travel and that the length of the core relative to the length ofthe internal bore of the casing is such as to permit appreciable travelof the core only within certain predetermined limits.

While the forms of apparatus herein described constitutes preferredembodiments of the invention, it is to be understood that the inventionis not limited to these precise forms of apparatus, and that changes maybe made therein without departing from the scope of the invention.

What is claimed is:

l. A thermally responsive valve comprising:

a. a valve casing having a first coefficient of linear thermalexpansion, means defining a bore extending longitudinally of saidcasing,

c. a valve core having a coefficient of linear thermal expansionappreciably different than that of said casing slidably received in saidbore,

d. abutment means positioned in said bore adjacent one end thereof,

e. abutment engaging means on said valve core positioned in oppositionto said abutment means for engagement therewith upon temperature change,

f. stop means positioned adjacent an opposite end of said bore,

g. stop engaging means of said valve core positioned in opposition tosaid stop means, and

. means for urging said stop engaging means into engagement with saidstop means.

2. The valve of claim 1 wherein:

a. said stop means comprises an enlarged portion of said bore definingan outwardly projecting shoulder.

. The valve of claim 2 wherein:

a. said means for urging said stop engaging means into contact with saidstop means comprises a spring member mounted in said enlarged portion ofsaid bore and pushing said stop engaging means toward said stop means.

4. The valve of claim 3 further comprising:

a. a retainer extending inwardly of said enlarged porb. means defining apocket formed in said core and receiving said spring member.

5. The valve of claim 1 wherein:

a. said stop engaging means comprises an outwardly projecting headformed on one end of said core in overlying relationship to said stopmeans.

6. The valve of claim 5 wherein:

a. said means urging said head into engagement with said stop meanscomprises a spring member, and

b. a retainer is mounted in said bore in engagement with said springmember and in spaced relationship to said stop means to retain saidspring in contact with said core.

7. The valve of claim 6 further comprising:

a. means defining a pocket in said one end of said core receiving saidspring member.

8. A thermally responsive valve comprising:

a. a valve casing having a longitudinally extending bore,

b. means defining an abutment adjacent one end of said bore and a stopadjacent an opposite end of said bore,

c. a valve core slidably received in said bore and having portionsadapted to engage said abutment and stop defining means,

d. the length and coefficient of linear thermal expansion of said corewith respect to the length of said bore and the coefficient of linearthermal expansion of said casing being such that:

i. said abutment and stop engaging means engage said abutment and stop,respectively, at a first temperature,

ii. said abutment engaging means is spaced from said abutment and saidstop engaging means engages said stop at a second temperature lower thansaid first temperature, and

iii. said abutment engaging means engages said abutment and said stopengaging means is spaced from said stop at a third temperature higherthan said first temperature.

. The valve of claim 8 further comprising:

a. means defining a flow port, and

b. means fixing said valve casing with respect to said flow port with aportion of said valve core positioned in said port,

c. said valve core being operative to vary the effective open area ofsaid flow port over a first temperature range and relatively inoperativeto vary said effective open area over a second temperature range.

10. The valve of claim 8 further comprising:

a. a portion of said bore adjacent one end thereof being of reducedcross section, forming an inwardly projecting shoulder defining saidabutment,

b. a second portion of said bore adjacent an opposite end thereof beingof enlarged cross section, forming an outwardly projecting shoulderdefining said stop,

0. a portion of said core adjacent said one end of said bore defining anoutwardly projecting shoulder disposed in oppositjon to and for engaement with said inwardly pro ecting shoulder 0 said bore upon expansionof said core,

d. a portion of said core adjacent said opposite end of said bore beingof enlarged cross section and defining a head positioned for engagementwith said outwardly projecting shoulder of said bore upon contraction ofsaid core, and

e. spring means resiliently urging said head into engagement with saidoutwardly projecting shoulder.

1 l. The valve of claim 4 wherein:

a. said valve casing has a relatively low coefficient of linear thermalexpansion, and

b. said valve core has a relatively high coefficient of linear thermalexpansion compared to said valve casing.

12. The valve of claim 7 wherein:

a. said valve casing has a relatively low coefficient of linear thermalexpansion, and

b. said valve core has a relatively high coefficient of linear thermalexpansion compared to said valve casing.

13. The valve of claim 10 wherein:

a. said valve casing has a first coefficient of linear thermalexpansion, and

b. said valve core a coefficient of linear thermal expansion appreciablydifferent than the coefficient of linear thermal expansion of said valvecasing.

14. The valve of claim 13 wherein:

a. said valve core has a coefficient of linear thermal expansionsubstantially greater than the coefficient of linear thermal expansionof said valve casing.

1. A thermally responsive valve comprising: a. a valve casing having afirst coefficient of linear thermal expansion, b. means defining a boreextending longitudinally of said casing, c. a valve core having acoefficient of linear thermal expansion appreciably different than thatof said casing slidably received in said bore, d. abutment meanspositioned in said bore adjacent one end thereof, e. abutment engagingmeans on said valve core positioned in opposition to said abutment meansfor engagement therewith upon temperature change, f. stop meanspositioned adjacent an opposite end of said bore, g. stop engaging meansof said valve core positioned in opposition to said stop means, and h.means for urging said stop engaging means into engagement with said stopmeans.
 2. The valve of claim 1 wherein: a. said stop means comprises anenlarged portion of said bore defining an outwardly projecting shoulder.3. The valve of claim 2 wherein: a. said means for urging said stopengaging means into contact with said stop means comprises a springmember mounted in said enlarged portion of said bore and pushing saidstop engaging means toward said stop means.
 4. The valve of claim 3further comprising: a. a retainer extending inwardly of said enlargedportion of said bore in spaced relation to said stop means and inengagement with said spring member, and b. means defining a pocketformed in said core and receiving said spring member.
 5. The valve ofclaim 1 wherein: a. said stop engaging means comprises an outwardlyprojecting head formed on one end of said core in overlying relationshipto said stop means.
 6. The valve of claim 5 wherein: a. said meansurging said head into engagement with said stop means comprises a springmember, and b. a retainer is mounted in said bore in engagement withsaid spring member and in spaced relationship to said stop means toretain said spring in contact with said core.
 7. The valve of claim 6further comprising: a. means defining a pocket in said one end of saidcore receiving said spring member.
 8. A thermally responsive valvecomprising: a. a valve casing having a longitudinally extending bore, b.means defining an abutment adjacent one end of said bore and a stopadjacent an opposite end of said bore, c. a valve core slidably receivedin said bore and having portions adapted to engage said abutment andstop defining means, d. the length and coefficient of linear thermalexpansion of said core with respect to the length of said bore and thecoefficient of linear thermal expansion of said casing being such that:i. said abutment and stop engaging means engage said abutment and stop,respectively, at a first temperature, ii. said abutment engaging meansis spaced from said abutment and said stop engaging means engages saidstop at a second temperature lower than said first temperature, and iii.said abutment engaging means engages said abutment and said stopengaging means is spaced from said stop at a third temperature higherthan said first temperature.
 9. The valve of claim 8 further comprising:a. means defining a flow port, and b. means fixing said valve casingwith respect to said flow port with a portion of said valve corepositioned in said port, c. said valve core being operative to vary theeffective open area of said flow port over a first tempErature range andrelatively inoperative to vary said effective open area over a secondtemperature range.
 10. The valve of claim 8 further comprising: a. aportion of said bore adjacent one end thereof being of reduced crosssection, forming an inwardly projecting shoulder defining said abutment,b. a second portion of said bore adjacent an opposite end thereof beingof enlarged cross section, forming an outwardly projecting shoulderdefining said stop, c. a portion of said core adjacent said one end ofsaid bore defining an outwardly projecting shoulder disposed inopposition to and for engagement with said inwardly projecting shoulderof said bore upon expansion of said core, d. a portion of said coreadjacent said opposite end of said bore being of enlarged cross sectionand defining a head positioned for engagement with said outwardlyprojecting shoulder of said bore upon contraction of said core, and e.spring means resiliently urging said head into engagement with saidoutwardly projecting shoulder.
 11. The valve of claim 4 wherein: a. saidvalve casing has a relatively low coefficient of linear thermalexpansion, and b. said valve core has a relatively high coefficient oflinear thermal expansion compared to said valve casing.
 12. The valve ofclaim 7 wherein: a. said valve casing has a relatively low coefficientof linear thermal expansion, and b. said valve core has a relativelyhigh coefficient of linear thermal expansion compared to said valvecasing.
 13. The valve of claim 10 wherein: a. said valve casing has afirst coefficient of linear thermal expansion, and b. said valve core acoefficient of linear thermal expansion appreciably different than thecoefficient of linear thermal expansion of said valve casing.
 14. Thevalve of claim 13 wherein: a. said valve core has a coefficient oflinear thermal expansion substantially greater than the coefficient oflinear thermal expansion of said valve casing.